title: Diffusion analysis with triexponential function in hepatic steatosis.
abstract: Our purpose was to assess the influence of liver steatosis on diffusion by triexponential analysis. Thirty-three patients underwent diffusion-weighted magnetic resonance imaging with multiple b values for perfusion-related diffusion, fast free diffusion, and slow restricted diffusion coefficients (D p, D f, D s) and fractions (F p, F f, F s). They also underwent dual-echo gradient-echo imaging for measurement of the hepatic fat fraction (HFF). Of these, 13 patients were included in the control group and 20 in the fatty liver group with HFF >5 %. The parameters of the two groups were compared by use of the Mann-Whitney U test. The relationships between diffusion coefficients and HFFs were assessed by use of the Pearson correlation. D p and D f were reduced significantly in the steatotic liver group compared with those in the control group (D p = 27.72 ± 6.61 × 10(-3) vs. 33.33 ± 6.47 × 10(-3) mm(2)/s, P = 0.0072; D f = 1.70 ± 0.53 × 10(-3) vs. 2.06 ± 0.40 × 10(-3) mm(2)/s, P = 0.0224). There were no significant differences in the other parameters between the two groups. Furthermore, D p and D f were correlated with HFF (P < 0.0001, r = -0.64 and P = 0.0008, r = -0.56, respectively). Decreased liver perfusion in steatosis caused the reduction in D p, and extracellular fat accumulation and intracellular fat droplets in steatosis led to the reduction in D f. Thus, the influence of hepatic steatosis should be taken into consideration when triexponential function analysis is used for assessment of diffuse liver disease.
authors.affiliation: Department of Radiological Technology, Toranomon Hospital, 2-2-2 Toranomon, Minato-ku, Tokyo, 105-8470, Japan, ja_nei3@yahoo.co.jp.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Hayashi
authors.forename: Tosiaki
authors.initials: T
authors.lastname: Miyati
authors.forename: Junji
authors.initials: J
authors.lastname: Takahashi
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Tsuji
authors.forename: Hidesato
authors.initials: H
authors.lastname: Suzuki
authors.forename: Naomi
authors.initials: N
authors.lastname: Tagaya
authors.forename: Mariko
authors.initials: M
authors.lastname: Hiramoto
authors.forename: Kei
authors.initials: K
authors.lastname: Fukuzawa
authors.forename: Masakatsu
authors.initials: M
authors.lastname: Tano
authors.forename: Satoshi
authors.initials: S
authors.lastname: Saitoh
mesh_terms: D000328:Adult; D000368:Aged; D004058:Diffusion; D038524:Diffusion Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D005234:Fatty Liver / Q000175:diagnosis / Q000473:pathology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008099:Liver / Q000473:pathology*; D008107:Liver Diseases / Q000175:diagnosis / Q000473:pathology; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results